All Questions
Tagged with pseudorepliction or pseudoreplication
25 questions
1
vote
1
answer
46
views
hierarchical model specification and pseudoreplication
I have an experiment where we measure the diameter of individual trees nested within plots. Plots are paired across the landscape, and one of the plots within pair is randomly assigned to treatment, ...
- 1,252
0
votes
0
answers
9
views
How do I account for replicates at the same sites when looking for spatial autocorrelation?
I am trying to examine the effect of spatial patterning/autocorrelation on a response variable at a number of sites distributed unevenly across a landscape (probably using Moran's I) but I'm unsure ...
1
vote
0
answers
26
views
Multiple regression and pseudoreplication
I have an experiment where fluke infection is estimated non destructively by 2 different assays at 3 separate time points. After a set number of weeks the animals are culled, the liver extracted and ...
0
votes
0
answers
12
views
Looking for references/resources to help explain why a design is pseudoreplicated to a colleague
A colleague and I are working on a project which involves sampling 15 different sites, and we collected 3 replicate samples at each site (to capture spatial variability, not repeated measures at an ...
- 121
3
votes
1
answer
65
views
Determining biological replicates with pooled samples
Our group has had a long-standing protocol wherein multiple tissue purifications are pooled. This is because there is very little of the tissue per animal. This pool was then sampled several times and ...
- 1,421
3
votes
3
answers
368
views
Which error bars to use when comparing only two subjects when many replicates?
I want to plot discrete time measurements made for two subjects, but where many cells were observed for each subject in triplicate.
I think the experimental unit is the subject, so I should just get a ...
0
votes
0
answers
16
views
Is there a best approach for statistical power for field experiment?
I'm setting up a field experiment and want to make a solid plan for the analysis, since that's whereI get stressed in the process. I will deploy 26 pairs of traps. 13 pairs will be in urban forest, ...
- 101
1
vote
0
answers
29
views
What counts as pseudo-replication?
I'm interested in adding a new factor to my data set (to model against my response), but I need help thinking through if doing so would introduce pseudo-replication, or other problems as well.
The way ...
- 2,091
3
votes
1
answer
164
views
How to handle Pseudoreplication - Aggregate observations per group for linear mixed model or take individual observations
I´m trying to fit a linear mixed model to test if my dependent variable (B) is different between my treatments (A with 2 levels A&B). The study was conducted at severals sampling sites. To account ...
- 33
0
votes
0
answers
59
views
I want to fit a linear regression model, but I know that if I treat each instance as unique there will be many pseudo replicates
I want to fit a linear regression model, but I know that if I treat each instance as unique there will be many pseudo replicates.
I want to explore the relationship between 2 binary variables and one ...
- 1
1
vote
0
answers
14
views
Analysing a dataset that has mainly independent records but now has a few paired records
I am at the start of a project that collects data from subjects every 3 months. The data I currently have is nearly all independent (one record per subject, see screengrab below) but we've just hit ...
- 11
3
votes
2
answers
62
views
Does this design indeed raise concerns about pseudoreplication?
We want to test the effect of dietary supplement on two groups of cows (randomized and controlled for starting weight and age). Group 1 (6 cattle) receives supplement 1 and group 2 (6 cattle) receives ...
- 131
1
vote
2
answers
307
views
meaning of independent samples
I am getting confused about the concept of independent samples, which is related to the concept of pseudoreplications. This question is related to this topic. But reading it does not make it clear for ...
- 1,714
1
vote
1
answer
40
views
How do I count replicates in chapter 1 of Crawley's book?
I am reading the second edition of Crawley's Statistics: An Introduction Using R and in the Pseudoreplication section of chapter 1 (pg. 15), he provides the following experiment structure:
"...
- 113
1
vote
0
answers
17
views
Does this experimental design avoid pseudo-replication?
I’m looking at a data set where 15 properties undertaking new management practices are sampled over three seasons. Measurements taken include variables such as vegetation cover and canopy cover. ...
2
votes
0
answers
132
views
Questions regarding pseudoreplication and required random effects
My problem
I would like to infer the relative importance of "habitat connectivity" compared to "habitat quality" to explain tits breeding success in a urban area (more details ...
- 651
1
vote
3
answers
1k
views
Which statistical test should be used to compare two groups with biological and technical replicates?
I'am conducting a drug screening experiment samples grouped by two conditions (expression or not of a specific molecular receptor). For the group expressing the receptor I have four diferent samples, ...
- 11
3
votes
1
answer
124
views
Are these data pseudoreplicated?
I have an amalgamation of independently collected datasets covering a large area of ocean where surveys to count birds have occurred sporadically over a long time. Some surveys were from boat, some ...
- 164
1
vote
0
answers
11
views
Include variance in regression on mean values
I have a data set on a biological variable in a wild population. I am interested in how that variable changes with respect to an environmental variable, temperature.
Given the constraints of sampling, ...
- 735
1
vote
2
answers
314
views
How does pseudoreplication differ from resampling
I wonder how pseudoreplication (https://en.wikipedia.org/wiki/Pseudoreplication) differs from resampling (which is simply resampling with replacement from a given sample).
On the one hand, resampling ...
- 1,921
1
vote
0
answers
229
views
Is it possible to affirm there is pseudoreplication in a design without making assumption on variable importance?
this is quite an abstract question, but I am trying to learn more of the basics in pseudoreplication.
Pseudo replication is defined by Hurlbert (1984) as:
Pseudoreplication may be defined , in ...
- 539
2
votes
1
answer
1k
views
incorporating biological replicates in one-way ANOVA
I'm measuring a particular property of worms (e.g. length, speed, ...). The worms are subdivided in 3 treatments (genetic strains) and each treatment group consists of 15 individuals. I replicated the ...
- 35
4
votes
2
answers
830
views
How do I analyze a three factor ANOVA without replication in R?
This summer, I conducted a growth chamber experiment testing the effects of the projected climate change conditions on the growth and survival of newly germinated seedlings of Acadian forest tree ...
- 41
3
votes
2
answers
309
views
Split plot design with psudo replicates
I am working on a project and need to analyze data that I know is an example of a split plot design but I am having trouble setting the model up correctly.
Here's the situation:
A bakery is testing ...
- 31
3
votes
0
answers
409
views
Pseudoreplication in a split-split plot design on count data in R
Agricultural Experimental design: a split-split plot in which a field is divided into 3 replications; each replication is divided into 2 to apply different pesticide spraying programs and each spray-...
KaatV